• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.11
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• pp.1141-1144
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• 2011

Range walk has been a major problem in achieving correct Doppler processing. This frequently occurs when range variation is severe just like in a bistatic radar or in high speed target scenario. This paper presents a range walk compensated range-Doppler processing algorithm applicable to the bistatic radar. In order for the compensation, a range-domain interpolation is applied for range compressed signal so that Doppler processing is performed along the evenly time-spaced range bins that contain target returns. Under a bistatic radar scenario, the proposed algorithm including a range domain pulse compression is mathematically described. Finally, the validity of the algorithm is demonstrated by simulation results showing the superiority of a SCDP(Squint Cross-range Doppler Processing) over an uncompensated Doppler processing.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.12B
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• pp.1244-1250
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• 2010

This paper presents a detection and ranging algorithm for a high-speed targets in the high PRF radar. We show, unlike the conventional methods, it firstly estimates Doppler frequency with a quasi-periodic pulse train prior to range processing. The estimated Doppler frequency can compensate the phase error enbeded in the received signal, which makes the signal integrated coherently in the range direction and localizes the target's signiture in low SNR. We present the derivation of the proposed algorithm and discuss how the system parameters such as the range/Doppler sampling condition, processing time and Doppler estimation error affect the performance of the proposed algorithm, which is verified by simulations.

• Proceedings of the KIEE Conference
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• 1987.07a
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• pp.26-29
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• 1987

This paper concerns methods for ${\mu}$-wave imaging. The image reconstruction of an object by range-doppler preceding using the X-Band Linear-FM signal is presented from tile simulated data. The high degree of range resolution is achived using large signal band width and cross-range resolution is obtained by doppler processing.

• Proceedings of the KIEE Conference
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• 1988.07a
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• pp.297-300
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• 1988

The ultrasound Doppler effect is used for measuring the velocity of the bloodflow in an artry. Because of the range information, the pulsed doppler system is most commonly used. In this paper, we propose a new pulsed doppler system which uses a quadrature sampling method in R.F. range in order to detect the bloodflow direction and to simplify the compexity of hardware. The pulsed doppler system using quadrature sampling method in R.F. range eliminates In-phase, Quadrature phase channel balancing problem at demodulator. In addition, the improved pulsed Doppler system shows the possibility of serial processing.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.6B
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• pp.1100-1105
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• 2000

The most widely used radar pulse compression technique is correlation processing using Barker code. This technique enhances detection sensitivity but, unfortunately, suffers from the addition of range sidelobes which sometimes will degrade the performance of radar systems. In this paper, our proposed optimal algorithm eliminates the sidelobes at the cost of additional processing and is evaluated in the presence of Doppler shift. We then propose optimal codes with regard to the proposed algorithm and the performance is compared against the traditional correlation processing with Barker codes. The proposed processing using optimal codes will be shown to be superior over the traditional processing in the presence of Doppler shift.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.40 no.1
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• pp.130-138
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• 2003

The classical image reconstruction for stripmap-mode Synthetic Aperture Radar is the Range-Doppler algorithm. When the spotlight-mode SAR system was envisioned, Range-Doppler algorithm turned out to fail rapidly in this SAR imaging modality. Thus, what is referred to as Polar format algorithm, which is based on the Plane wave approximation, was introduced for imaging from spotlight-mode SAR raw- data. In this paper, we have studied for the raw data processing schemes in the spotlight-mode Synthetic Aperture Radar. We apply the Wavefront Reconstruction scheme that does not utilize the approximation in spotlight-mode SAR imaging modelity, and compare the performance of target imaging with the Polar format inversion scheme.

• Proceedings of the IEEK Conference
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• 2001.06d
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• pp.167-170
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• 2001

A low power pulse Doppler radar should integrate a large number of data to provide a required maximum detectable distance. Doppler filter needs a window that has good out-of-bard rejection level to maintain high dynamic range. From these facts, we can apply decimation and presumming to increase the speed of Doppler processing. This Paper investigates the efficiencies of several decimation methods and the loss of presumming. And I propose a method to increase processing speed but to maintain the maximum detectable distance.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.6
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• pp.125-133
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• 2016

As one of solutions to pursue the efficient use of spectrum resource, we proposed the methodology for the co-channel multi-site radar operations with the synchronous GPS clock. The proposed algorithm, based on a quasi orthogonal property, find a candidate set of the time shifted linear frequency modulation(TSLFM) signals with the minimum acceptable level of the correlation among selected TSLFM signals. To check suggested algorithm, numerical analysis for several radars operating in the same channel with a sawtooth waveform has been performed by using range-Doppler processing for the given system parameters, and computational results are presented and examined in terms of range profile and doppler shift for a targets with velocity and distance. Simulated results have a good agreement with assumed target distance and its velocity, within the error of resolution.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.9
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• pp.740-748
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• 2017

In this paper, we compared performance of conventional inverse synthetic aperture radar(ISAR) imaging methods for maritime target with real data measured by X-band radar. Following conventional approaches were used for performance comparisons: 1) range instantaneous Doppler(RID) method, 2) range Doppler(RD) processing with phase adjustment, and 3) RD processing with prominent point processing(PPP). It is noteworthy that the comparison results have significance of providing basic concept to establish ISAR imaging frame work for maritime targets.

• Korean Journal of Remote Sensing
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• v.23 no.4
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• pp.247-256
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• 2007

In this paper we introduced GB-SAR focusing algorithms for image formation and suggested an optimized solution. We compared the characteristics, advantages, and limitations of the Deramp-FFT (DF) algorithm and the Range-Doppler (RD) algorithm in terms of their image formation principles, memory usage and processing time. We found that DF algorithm is efficient in memory and processing time but can not focus the near range. The RD algorithm can focus the entire range but, considering the refinement on the rail length, it has much redundancy in memory and processing time. In conclusion, we optimized the GB-SAR focusing by using the DF algorithm for a far-range case and the RD algorithm for a near-range case separately.